Significantly enhanced energy density is obtained at a low electric field by embedding aligned BaTiO3 nanowires in a polymer matrix via a new physical-assisted casting method.

Ever since the beginning of this century, many kinds of materials have been reported to demonstrate colossal permittivity (CP) or colossal dielectric constant exceeding 10 3 . Accordingly, such CP materials and their further modification and improvement to achieve enhanced CP performance for promising applications in modern electronics, sensors, energy storage, and multifunctional devices and so on have attracted extensive attention. In this review, 2 a general overview of the recent advances in CP materials is provided, ranging from their various categories, physical mechanisms, and modulation methods to promising applications.First, various classes of CP materials are categorized in terms of their structures and dielectric properties. Subsequently, this review provides an insight into the CP mechanisms in views of barrier layer capacitance, defect-dipole cluster and polaronic effect. Moreover, the strategies and prototypical works are introduced in some aspects, including the manipulation of CP properties by doping, percolative capacitors and the methods employed to enhance the dielectric behaviors in CP materials with different forms. We then discuss a wide range of applications based on CP materials, such as modern electronics and energy storage. Finally, the challenges and opportunities for further investigation of CP materials are highlighted in the summary and future perspectives.

A low dielectric loss (<0.01) in (Mg + Nb) co-doped TiO2 rutile ceramics will further highlight the development of colossal permittivity materials for practical applications.

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Effect of isovalent Zr dopant on the colossal permittivity (CP) properties was investigated in (Zr + Nb) co‐doped rutile TiO2 ceramics, i.e., Nb0.5%ZrxTi1−xO2. Compared with those of single Nb‐doped TiO2, the CP properties of co‐doped samples showed better frequency‐stability with lower dielectric losses. Especially, a CP up to 6.4 × 104 and a relatively low dielectric loss (0.029) of x = 2% sample were obtained at 1 kHz and room temperature. Moreover, both dielectric permittivity and loss were nearly independent of direct current bias, and measuring temperature from room temperature to around 100°C. Based on X‐ray photoelectron spectroscopy, the formation of oxygen vacancies was suppressed due to the incorporation of Zrions. Furthermore, it induced the enhancement of the conduction activation energy according to the impedance spectroscopy. The results will provide a new routine to achieve a low dielectric loss in the CP materials.